Single quantum dot imaging in live cells: towards a cellular GPS

摘要

Colloidal semiconductor quantum dots (QDs) have become common fluorescent probes in biology. Their optical properties not only facilitate spectrally multiplexed detection but also enable single molecule measurements with high signal to noise ratio. This is of particular interest in cell biology since it allows individual QD-tagged biomolecules to be tracked with good spatial and temporal resolution over long durations. Recent measurements on membrane proteins have validated this approach and serve as a basis for more complex experiments in which the motion of different biomolecules, located in various cell compartments (membrane, cytosol, nucleus,...) and tagged with QDs having distinct emission colors, is recorded in real time and with a nanometer resolution. The development of these new imaging methods, equivalent to a molecular positioning system within a single cell, raises many challenges, coming from optics, physical and biological chemistry, as well as image processing.